Dredger having separately floating dredge and tail sections and method of dredging

ABSTRACT

Underwater excavating apparatus including a floatable, anchorable tail section and a floatable, anchorable dredge section mounted on the tail section for longitudinal and swinging movement. The dredge section is swung relative to the tail section to dredge a swath and then advanced longitudinally relative to the tail section for cutting additional swaths. After being extended to its limit relative to the tail section, the dredge section is then anchored and the tail section unanchored and moved longitudinally up to its original position adjacent the dredge section after which the process is repeated.

A United States Patent [191 Smith 1 DREDGER HAVING SEPARATELY FLOATINGDREDGE AND TAIL SECTIONS AND METHOD OF DREDGING [76] Inventor: Leward N.Smith, Millbrook Road,

Rte. 1, Remus, Mich. 48757 [22] Filed: Nov. 19, 1973 21] Appl. No.:417,097

[52] US. Cl. 37/67; 37/73; 37/195;

[51] Int. C1. E02F 3/88 [58] Field of Search 37/67, 66, 73, 72, 58,

37/54, 195; 114/235 R; 115/9; ISO/79.2 B; 61/465 [56] References CitedUNITED STATES PATENTS 357,880 2/1887 Walsh 37/67 X 515,379 2/1894Titcomb 37/73 601,524 3/1898 Parker 37/58 703,817 7/1902 Perry 37/58Nov. 18, 1975 1,019,610 3/1912 Donnelly 37/67 2,061,440 11/1936 Schaefer2,109,730 3/1938 Le Tourneau 37/73 2,614,644 10/1952 Gustafson 180/792 B3,230,721 l/l966 DeLong et al. 37/54 X Primary E.rarninerClifford D.Crowder [57] ABSTRACT Underwater excavating apparatus including afloatable, anchorable tail section and a floatable, anchorable dredgesection mounted on the tail section for 1ongitudinal and swingingmovement. The dredge section v is swung relative to the tail section todredge a swath and then advanced longitudinally relative to the tailsection for cutting additional swaths. After being extended to its limitrelative to the tail section, the dredge section is then anchored andthe tail section unanchored and moved longitudinally up to its originalposition adjacent the dredge section after which the process isrepeated.

10 Claims, 8 Drawing Figures US. Pamnt Npv.18,1975 Sheet10f4 3,919,791

US. atent Nov. 18, 1975 Sheet 2 of 4 FIG.2

US. Patent Nov. 18,1975 Sheet3of4 3,919,791

Patant Nov. 18, 1975 Sheet4 Of4 3,919,791

DREDGER HAVING SEPARATELY FLOATING DREDGE AND TAILSECTIONS AND METHOD OFDREDGING BACKGROUND OF THE INVENTION This invention relates tounderwater excavating apparatus of the type including a floatabledredging hull scribed which initially forwardly moves the dredgeseccarrying a cutterhead which removes underwater matel0 rial, such asearth. One such apparatus is disclosed in applicants copending patentapplication Ser. No. 221,538, filed inthe US. Patent Office on Jan. 28,1972, now U.S. Pat. No. 3,777,375 and incorporated herein by reference.The apparatus disclosed in the copending patent application includes apair of anchoring spuds, one which is generally anchored immediatelybelow the dredge, and a pair of anchor cables which are anchored in firmearth on opposite sides of the bog being excavated. The spuds arealternately and oppositely moved to and from an anchoring position and awinch, mounted on the dredge hull, alternately winds and unwinds theanchor cables to swing the dredge in alternate directions about theanchored spud to step the dredge forwardly in a manner more particularlydescribed in the referenced patent application. Depending on thedistance stepped forwardly and the are through which the dredge sectionis swung, the arcuate path of the cutterhead will sometimes partiallyoverlap a portion of the previous path of the cutterhead thus decreasingthe dredging efficiency. Also, the path of the cutterhead is such that astrip of undredged material is sometimes skipped, necessitatingfollow-up excavating to remove the uncut material. The time required toanchor one spud and release the other spud each time the dredge isstepped forwardly also decreases the operating efficiency.

After the prior art dredging apparatus is stepped forwardly apredetermined number of times, the anchoring cables are moved forwardlyand reanchored. Movement of the cables is a very difficult task, andcauses substantial operating down time for the dredge. Such breaks alsointerrupt the dredging momentum which a dredge operator builds.

The degree of swing of the prior art dredging apparatus is effectivelylimited to approximately a 90 arc. If the dredge is swung beyond a 90arc, the anchoring cables tend to pull the anchored spud from theunderwater earth. Accordingly, it is an object of the present inventionto provide underwater excavating apparatus which will have asubstantially increased dredging capacity and efficiency.

It is another object of the present invention to provide apparatus andmethod of the type described which will increase the arc through whichthe dredge cutterhead is swung. s

It is another object of the present invention to provide an underwaterexcavating apparatus and a method which will eliminate the use ofanchoring cables for swinging the dredge hull and will eliminate therequirement for anchoring a different spud each time the cutterhead isstepped forwardly.

A further object of the present invention is to provide dredgingapparatus of the type described including a floatable dredging sectionwhich is longitudinally movable on an anchored tail section.

Still another object of the present invention is to provide dredgingapparatus of the type described which tion on an anchored tail sectionand then forwardly moves the tail section on an anchored dredge section.

A further object of the present invention is to provide apparatus of thetype described which will minimize the loading on the anchoring spuds.

A still further object of the present invention is to provide apparatusof the type described including new and novel mechanism for relativelyswinging the dredge and tail sections.

Other objects and advantages of the present invention will becomeapparent to those of ordinary skill in the art as the descriptionthereof proceeds.

SUMMARY OF THE INVENTION Apparatus and method for excavating material,such as earth, from an underwater basin including an anchorable tailsection, and a dredge section which is mounted for incremental indexingforward movement on the tail section and is also horizontally swingablerelative to the tail section.

The present invention may more readily be understood by reference to theaccompanying drawings in which:

FIG. 1 is a top plan view of apparatus constructed according to thepresent invention;

FIG. 2 is a partly sectional, side elevational view of the apparatusillustrated in FIG. 1, parts being broken away;

FIG. 3 is an enlarged, sectional, top plan view, taken along the line3-3 of FIG. 2;

FIG. 4 is an enlarged, sectional end view, taken along the line 4-4 ofFIG.

FIG. 5 is an enlarged, sectional, end view taken along the line 5-5 ofFIG. 1;

FIG. 6 is a schematic top plan view illustrating the path of travel of aprior art dredge cutterhead;

FIG. 7 is a top plan schematic view illustrating the path of travel of acutterhead constructed according to the present invention; and

FIG. 8 is a slightly enlarged, partly sectional, side elevational viewof one ofthe anchoring spuds and the apparatus for lifting the spud.

Apparatus constructed according to the present invention comprises aforward, floatable dredging section, generally designated 10, and arear, floatable tail section, generally designated 12. The floatabletail section 12 includes an elongate framework 14 spanning a pair oflongitudinally spaced, hollow floatation devices 16 which aresufficiently buoyant to floatably support the tail section 12 on thewater, generally designated W. The elongate framework 14 includes pairsof upper and lower longitudinal rails 15 which are spanned by verticalrails 15a and vertically inclined rails 15c, and connected by horizontalrails 15d. Mounted on the tail section 12 are a plurality of spud wells,generally designated 20, slidably receiving vertically movable spuds 22which, when partially buried in the underwater earth E as illustrated inFIG. 2, anchor the tail section 12. Apparatus is provided for verticallyretracting the spuds 22 and comprises a plurality of double acting,solenoid actuated, fluid pressure operated cylinders 24 (FIG. 8)actuating piston rods 26 which are connected to cables 28 trained aroundidler pulleys 29 mounted r 3 on the frame 14, and idler pulleys 30,mounted on the spud wells 20. The ends 28a of the cables 28 are fastenedto the lower ends 22a of the spuds 22. When the piston rods 26 areretracted, the spuds 22 are removed from the earth E.

The floatable dredge section 10 is of the type described in US. Pat.Nos. 2,732,741 and 2,944,352, which are incorporated herein byreference. The hull l mounts a vertically movable dredge latter 23 whichis vertically moved in a manner described in the referenced patentapplication. Rotatably mounted on the front of the dredge ladder 23 isrotatable, generally hollow, excavating cutterhead 25 for digging andcollecting earth. A rotatable, cutterhead drive shaft 27 is connectedwith the rotary cutterhead 25 and is driven by a suitable hydraulicmotor 29, mounted on the dredge ladder 23. A suction pipe 34, mounted onthe dredge ladder 23, is connected at its rearward end to the inlet sideof a dredge suction pump 32 supported on the hull 10. The pump 32 isdriven by a suitable Diesel or electric motor 38. An outlet pipe orsleeve 36 is connected to the output side of the pump 32 and deliversthe earth-water slurry sucked up by the pump 32 to a remote location.

Apparatus is also provided for anchoring the dredging hull section 10and comprises a pair of vertical spuds 40 slidably received in spudwells 42 mounted on the stern of the hull 10. The dredge sectionanchoring spuds 40 are moved vertically by apparatus which is supportedby the hull 10 and is constructed identically to the apparatusillustrated in FIG. 8 for raising the spuds 22 on the tail section 12.The spuds 40 are lowered to anchoring position when the tail section 12spuds 22 are raised to permit tail section 12 to be moved toward thedredge section 10 as will be described more particularly hereinafter.

An intermediate hull section 11, includes an elongate frameworkgenerally designated 44. Guides 46 (Figures 2 and mounted on theintermediate hull framework 44, are provided with recesses 47 lined withwearresistant guide bushings 43 which slidably receive longitudinallyextending rails or tracks 49 provided on laterally opposite, upper sidesof the tail section 12 or framework 14. The tail section 12 mounts apair of similar guides 46, which are inverted relative to the guides 46,including recesses 47 lined with nylon bushings 43 which slidablyreceive longitudinal guide rails 49 extending along and mounted to thelaterally opposite, lower sides of the upper framework 44. The guides46, 46 and rails 49, 49' permit the intermediate hull section 11 and thetail section 12 to be relatively longitudinally slid.

The stem of the dredge hull section includes a pair of verticallyspaced, rearwardly extending, hinge or connector plates 48 which areconnected to a pair of vertically spaced, hinge or connector plates 50,provided on the front end'of the intermediate framework 44, by avertical hinge or pivot pin 52. The latter sides 48a and 50a of thehinge plates 48 and 50 converge toward the pivot pin 52 to provide wide,angular spaces between the hinge sections 48 and 50 to permit maximumswinging movement of the dredge section 10 and the tail section 12.

Apparatus, generally designated 51, is provided for swinging the dredgesection 10 on the tail section 12 and includes a bar 54 freely swingablymounted on the hinge or pivot pin 52. The swinging apparatus 51 includesa plurality of double-acting, fluid pressure operated, solenoid actuatedcylinders 56, 60, and 58, 62 pivotally connected to the dredge hullsection 10 and the tail section 12 respectively, including piston rods56a, 60a, and 58a, 62a, pivotally connected to opposite ends of the bar54. When the tail section 12 is anchored and the piston rods 56a and 58aare extended, and the piston rods 60a and 62a are concurrentlyretracted, the hull 10 is swung counterclockwisely, in the direction ofthe arrow a (FIG. 3), to shift the hull 10 in an arcuate path about theaxis of hinge pin 52 to the position illustrated in chain lines in FIG.3. When the piston rods 56a and 58a are retracted and the piston rods60a and 62a are extended, the hull 10 is swung oppositely, in thedirection of the arrow b (FIGS. 1 and 3), to the position illustrated at10b.

Apparatus is provided for indexing the intermediate framework 44 and theunanchored dredge section 10 forwardly and rearwardly on the anchoredtail section 14 and comprises a motor 160, mounted on the intermediateframe 44, driving an endless chain 162 which is trained around asprocket 64, fixed to a shaft 67 journaled on the frame 44. Fixed to theshaft 67 is a smaller diameter sprocket 66. A chain 68, having its ends68a and 68b fixed to the rails 15 of the tail section 14, is trainedaround the sprocket 66 and a pair of idler sprockets 70 rotatablymounted on the upper framework 44. When the motor 160 is operated, thesprocket 64 will force the sprocket 66 to travel along the stationarychain 68 to move the framework 44 and dredge section 10 forwardly. Arack and a pinion drive gear could be substituted for the sprocket 66and chain 68 if desired. The slurry discharge tube 36 includes anexpansible section (not shown) to permit limited forward movement of thedredge section 10 relative to the tail section 14.

THE OPERATION I To condition the machine for operation, the spuds 22 onthe tail section 14 are lowered to anchoring position, and the spuds 40on the dredge section 10 are raised to the non-anchoring position, asillustrated in FIG. 2. Initially, the dredging hull section 10 will bepresumed to be at a position illustrated at in FIG. 7 and the cutterhead25 is in the position illustrated at 25a. The dredge hull swingingcylinders 56 and 58 are operated to alternately extend and retract thepiston rods 56a and 58a while the cylinders 60 and 62 are concurrentlyoppositely operated to retract and extend the piston rods 60a and 62a.When the piston rods 56a and 58a are firstly extended, and the pistonrods 60a and 62a are firstly retracted, the hull l0 and cutterhead 25will swing to the positions illustrated at 10b and 25b respectively inFIG. 7, to cut a swath 70. After this occurs, the motor 162 is operatedto index the framework 44 and the floatable dredge hull 10 bodilyforwardly to the positions illustrated in chain lines at 25c and 10e(FIG. 7). The pistons 60a and 62a are then extended and the pistons 56aand 58a are then retracted so that the cutterhead 25 cuts the next swath72 as it moves to the position illustrated at 25f.

The motor 162 is again operated to index the framework 44 and the hull10 forwardly so that the cutterhead 25 is positioned at 25g. The pistons56, 58, 60 and 62 are continued to be operated to swing the cutterhead25 is positioned at 25g. The pistons 60a, 58a, 60a and 62a are continuedto be operated to swing the cutterpositioned on the tail section 12, asillustrated in chain lines in FIG. 2. When this occurs, the spuds 40 onthe dredge section are then lowered to anchoring position, illustratedin chain lines in FIG. 2, and the spuds 22 on the tail section 12 areraised to the positions removed from the underwater earth-E. The'motor160 is then reversely operated to draw the tail section 12 forwardly,relative to the now stationary dredge section 10. When the hull sectionis returned to the position illustrated in FIG. 2, the tail sectionspuds 22 are again lowered and the dredge section spuds 40 are raised sothat the dredge hull section 10 can again be swung and advancedforwardly relative to the tail section 12.

The significance of applicants invention can be better appreciated bycomparing its operation with a typical prior art dredging operation,schematically illustrated in FlGQ6, wherein spuds 40, on the rear of adredge hull 10 are alternately embedded in the earth E as the device isstepped forwardly after each cut. Assuming that the right spud 40a (FIG.6) is initially in the ground, as the cutterhead 25 swings clockwiselyas is illustrated by the arrow r (FIG. 6), it will cut a swathdesignated by vertical cross-hatch lines at 74. When the cutterhead 25is swung to the right, to the position illustrated at 26a, the otherspud 40b is then buried in the earth and the spud 40a is retracted. Thedredge section then is swung in an opposite direction (opposite thedirection represented by the arrow r) so that a swath, designated byhorizontal cross-hatching 76, is taken. In the horizontallycross-hatched area, the path 76 of the cutterhead 25 overlaps at 70a theprevious swath 74 which reduces the dredging efficiency. the areadesignated 80 represents a gap of earth between the swaths 74 and 76which has been missed and which must be subsequently dredged. Not onlyis there substantial overlapping with the prior art dredge, but theswing of the cutterhead is substantially limited. If the arc isextended, the force on the anchored one of the spuds 40a and 40b tendsto pull the anchored spuds out of the earth B.

As illustrated in FIG. 7, the cutterhead 25 in the dredge of the presentinvention can swing through an angle of 90 from either side of a centerplane p. Up to 45 on either side of the plane p, there is substantiallyalmost no overlap. A swing of 60 on either side of the center plane pautomatically widens the cut by onethird, and therefore reduces thenumber of pipe set-ups for the conduit 36.

It is to be understood that the drawings and descriptive matterare inall cases to be interpreted as merely illustrative of the principles ofthe invention, rather than as limiting the same in any way, since it iscontemplated that various changes may be made in various elements toachieve like results without departing from the spirit of the inventionor the scope of the appended claims.

I claim 1. Apparatus for excavating material, such as earth, from anunderwater basin to enlarge the basin, com prising:

a floatable tail section;

a longitudinally aligned separately floated dredge section, displaceablelongitudinally relative to the tail section, and including a dredginghead for digging and collecting material to be dredged;

means for selectively anchoring said tail section in position;

means connecting the dredge section with said tail section for forwardlongitudinal movement relative to the tail section, and for generallyhorizontal 6 swinging movement relative to th tail section in variousrelative longitudinal positions of the dredge section and tail sectionwhen the tail'se'ction is anchored in position and the dredge section isunanchored; meansfor incrementally forwardly bodily longitudinallyindexing said dredge section to various positions of extension relativeto said tail section;

- and means reactive betweenisaid tail and dredge sectionsforlswingingsaid dredge section relative to said tailsection in various relativelongitudinally extended positions of said dredge section fromsaid tailsection, when the tail section is anchored and the dredge section isunanchored, to dredge material from said basin.

2. Apparatus as set forth in claim 1 wherein both said sections areselectively anchorable and said means for relatively bodily indexingsaid dredge section is operable to move said tail section toward saiddredge section when said dredge section is anchored and said tailsection is not anchored.

3. Apparatus as set forth in claim 1 wherein said means reactive betweensaid tail and dredge sections includes a bar swingably mountedinterjacent said tail and dredge sections, and sets of fluid pressureoperated, extensible and retractable power cylinders c0nnected betweenopposite ends of said bar and said sections.

4. The apparatus of claim 1 wherein the means connecting the dredgesection with the tail section comprises relatively telescoping membersand said means reactive for swinging the dredge section relative to thetail section is connected to one of said members.

5. The apparatus as set forth in claim 1 in which said tail sectionincludes a telescoping framework attached to said dredge section andfurther comprises a plurality of separate floats for supporting theframework.

6. The apparatus as set forth in claim 1 in which means is also providedfor selectively anchoring said dredge section in position and said tailand dredge sections have vertical guides; said anchoring means for bothsections comprising raisable and lowerable spuds movable in said guidesfrom a lowered position anchored in the basin bottom to a raisedunanchored position, and mechanism for selectively raising and loweringsaid spuds.

7. The apparatus as set forth in claim 1- in which said tail sectionsupports an elongate slide frame; an extensible slide boom is supportedby said slide frame and is extendible longitudinally forwardlytherefrom; said means mounting the dredge section for swinging movementrelative to the tail section, comprising a vertical pivot part carriedby said boom and to which said dredge support section is connected forhorizontal swinging movement.

8. The apparatus of claim 7 in which said reactive means compriseextensible and retractible, fluid pressure operated power cylindersconnected between said pivot part and dredge section and between saidpivot part and tail section.

9. A method of excavating material, such as earth, from an underwaterbasin with a dredge having an anchored floating dredge cutterheadsupport section piv- 3,919,791 7 8 reacting the unanchored dredgecutterhead support 10. The method of claim 9 including the further stepssection with the anchored tail section by using the of; tail section asa fixed support to horizontally swing anchol'mg 531d dredge cutterheadpp Sectlon the dredge cutterhead support section in an arcu- 5 b a}? frinigd said tailts ecnpn; d d dr d e ate path of travel relative to theanchored tail sec- 1y movmg a F Q e g cutterhead support section byusing the dredge cuttiotnhiancil dredging material while traveling insaid terhead pp Section as a fixed pp and pa 3 an acting against it; andrepemwely bofmy extendmg the dredge cutterhead the reanchoring said tailsection and unanchoring P furthe? forwardly f the anchored said dredgecutterhead support section so that the tall Section and repetltlvelySwmgmg the dredge dredge cutterhead support section can again be ex-Cutterhead pp Section in an arcuate P tended from the tail section andswung in a dredglowing said repetitive extensions to dredge mateing arcof travel. riaL UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OFCORRECTION O PATENTNO.: 3,919,791

DATED November 18, 1975 INVENTOR(S) Leward N; Smith It is certifiedthaterror appears in the above-identified patent and that said LettersPatent 9 are hereby corrected as shown below:

Column 1, lines 16, after "one" insert of Column 3, line 7, Change"2,732,741" to 2,731,741; line 43, change "or" to on line 58, change"latter" to lateral Column 4, lines 63, 64, and 65, delete "The pistons56, 58,

60 and 62 are continued to be operated to swing the cutterhead 25 ispositioned at 25g."; line 66, after "cutter-" insert head 25 and themotor 162 is intermittently operated until the intermediate framework 44is fully forwardly Column 5, line 30, after the period change "the" toThe Q Column 8, line 9, change "the" to then Signed and Scaled thissecond Day Of March 1976 v [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer 1 Commissioneroj'Patents and Trademarks

1. Apparatus for excavating material, such as earth, from an underwaterbasin to enlarge the basin, comprising: a floatable tail section; alongitudinally aligned separately floated dredge section, displaceablelongitudinally relative to the tail section, and including a dredginghead for digging and collecting material to be dredged; means forselectively anchoring said tail section in position; means connectingthe dredge section with said tail section for forward longitudinalmovement relative to the tail section, and for generally horizontalswinging movement relative to the tail section in various relativelongitudinal positions of the dredge section and tail section when thetail section is anchored in position and the dredge section isunanchored; means for incrementally forwardly bodily longitudinallyindexing said dredge section to various positions of extension relativeto said tail section; and means reactive between said tail and dredgesections for swinging said dredge section relative to said tail sectionin various relative longitudinally extended positions of said dredgesection from said tail section, when the tail section is anchored andthe dredge section is unanchored, to dredge material from said basin. 2.Apparatus as set forth in claim 1 wherein both said sections areselectively anchorable and said means for relatively bodily indexingsaid dredge section is operable to move said tail section toward saiddredge section when said dredge section is anchored and said tailsection is not anchored.
 3. Apparatus as set forth in claim 1 whereinsaid means reactive between said tail and dredge sections includes a barswingably mounted interjacent said tail and dredge sections, and sets offluid pressure operated, extEnsible and retractable power cylindersconnected between opposite ends of said bar and said sections.
 4. Theapparatus of claim 1 wherein the means connecting the dredge sectionwith the tail section comprises relatively telescoping members and saidmeans reactive for swinging the dredge section relative to the tailsection is connected to one of said members.
 5. The apparatus as setforth in claim 1 in which said tail section includes a telescopingframework attached to said dredge section and further comprises aplurality of separate floats for supporting the framework.
 6. Theapparatus as set forth in claim 1 in which means is also provided forselectively anchoring said dredge section in position and said tail anddredge sections have vertical guides; said anchoring means for bothsections comprising raisable and lowerable spuds movable in said guidesfrom a lowered position anchored in the basin bottom to a raisedunanchored position, and mechanism for selectively raising and loweringsaid spuds.
 7. The apparatus as set forth in claim 1 in which said tailsection supports an elongate slide frame; an extensible slide boom issupported by said slide frame and is extendible longitudinally forwardlytherefrom; said means mounting the dredge section for swinging movementrelative to the tail section, comprising a vertical pivot part carriedby said boom and to which said dredge support section is connected forhorizontal swinging movement.
 8. The apparatus of claim 7 in which saidreactive means comprise extensible and retractible, fluid pressureoperated power cylinders connected between said pivot part and dredgesection and between said pivot part and tail section.
 9. A method ofexcavating material, such as earth, from an underwater basin with adredge having an anchored floating dredge cutterhead support sectionpivotally connected with an unanchored separately floated tail sectioncomprising the steps of: anchoring the floatable tail section andunanchoring the dredge cutterhead support section; reacting theunanchored dredge cutterhead support section with the anchored tailsection by using the tail section as a fixed support to horizontallyswing the dredge cutterhead support section in an arcuate path of travelrelative to the anchored tail section, and dredging material whiletraveling in said path; and repetitively bodily extending the dredgecutterhead support section further forwardly of the anchored tailsection and repetitively swinging the dredge cutterhead support sectionin an arcuate path following said repetitive extensions to dredgematerial.
 10. The method of claim 9 including the further steps of:anchoring said dredge cutterhead support section and unanchoring saidtail section; bodily moving said tail section toward said dredgecutterhead support section by using the dredge cutterhead supportsection as a fixed support and reacting against it; and the reanchoringsaid tail section and unanchoring said dredge cutterhead support sectionso that the dredge cutterhead support section can again be extended fromthe tail section and swung in a dredging arc of travel.